Abstract
Electrical resistivity measurements are increasingly being used as measurements for concrete acceptance in practice. It has been shown that these measurements are sensitive to temperature. This paper examines the influence of temperature on electrical resistivity measurements in concrete. Two temperature correction approaches that are commonly used by researchers and practitioners were evaluated: a linear temperature correction approach (α) and an activation energy-based temperature correction approach (Ea-cond). These approaches were compared with each other and their predictive capabilities were assessed using measured data from various concrete mixtures. It was found that for cases of low temperature sensitivity (low values of α or Ea-cond), the predictions obtained with α and with Ea-cond were similar. However, the Ea-cond approach was found to provide more accurate corrections (lower error) than corrections using α for measurements conducted at lower temperatures and for systems with higher temperature sensitivities (high values of α or Ea-cond). For saturated concrete specimens, both the linear (α) and activation energy (Ea-cond) approaches are acceptable, whereas the use of the Ea-cond approach provides better predictive capabilities in sealed concrete specimens, especially at low temperatures. The average values for Ea-cond were found to be 29.8 kJ/mol for sealed specimens and 15.8 kJ/mol for saturated specimens, and corresponding average values of α are 3.25 %/°C and 2.00 %/°C, respectively. The values for Ea-cond for saturated specimens are closer to what is expected of a pore solution on its own.
